To meet extremely increasing demands for LCD glass substrates and the necessary low thermal stress in fabrication therefor for growing development of the mobile phone and liquid crystal display (LCD) TV industry, the method of thermal rupture by laser now gradually supersedes traditional diamond blade abrasion and laser melting for cutting, and becomes a leading method in LCD glass substrate fabrication of the next generation electro-optical industry.
The method of thermal rupture by laser is differentiated from laser melting in that the principle of thermal rupture is applied in the process of cutting. Due to the uniform laser thermal effects and finite affected surface range thereby, the advantages of sharp and flat cut surface, low residual thermal stress, and high speed in fabrication process are far unachievable to traditional methods of laser melting and diamond blade.
Gas state CO2 laser and solid state YAG laser respectively with wavelengths of 10.6 μm and 1.064 μm are currently applied in the business. Stable laser through an optical lens is focused to provide a thermal field on a glass substrate. Subsequently, adequate cryogenic effects are provided thereon to initiate a primary crack on the edge thereof. The crack develops steadily through the stress intensity factor field formed by the thermal and cryogenic fields, through which a desired cutting result is presented. However, the arrangements for cooling and heating sources are tested by trial to obtain optimal parameters for laser cutting, and therefore related principles of speed and configuration of cutting are comparatively absent.
In order to overcome the drawbacks in the prior art, a method for cutting a nonmetal material is proposed through arduous experiments and research.